add test for #427, now solved

Author: kyleheadley

clang/test/3C/overconstrained_merge.c

@@ -0,0 +1,19 @@
+// RUN: rm -rf %t*
+// RUN: 3c -base-dir=%S -alltypes -addcr %s -- | FileCheck -match-full-lines %s
+// RUN: 3c -base-dir=%S -alltypes -addcr %s -- | %clang -c -fcheckedc-extension -x c -o /dev/null -
+// RUN: 3c -base-dir=%S -output-dir=%t.checked -alltypes %s --
+// RUN: 3c -base-dir=%t.checked -alltypes %t.checked/overconstrained_merge.c -- | diff %t.checked/overconstrained_merge.c -
+
+// Test checks for merging a function after the generics code adds a constraint
+// The merge succeeds because it happens earlier in the codebase than the addition
+
+// This test only uses -alltypes because of the use of _Array_ptr in the example
+// (to distinguish from the _Ptr that will be added).
+_Itype_for_any(T) void free(void * : itype(_Array_ptr<T>));
+void b(void) {
+  char **c;
+  free(c);
+  // CHECK: _Array_ptr<_Ptr<char>> c = ((void *)0);
+  // CHECK: free<_Ptr<char>>(c);
+}
+void free(void *);